David Silva has only an outside chance of playing in Manchester City's FA Cup semi-final against Chelsea on Sunday because of a suspected hamstring tear. Roberto Mancini will give the midfielder until Saturday to prove his fitness before making any decision about his team in the hope the injury is not as bad as feared.

Silva suffered the problem in the closing moments of Monday's 2-1 derby win over Manchester United at Old Trafford. Following the match Mancini struck a pessimistic note about Silva's hopes of being available, saying "I don't think he will be ready for Chelsea". The 27-year-old had a scan on Wednesday and it is suspected that the muscle is torn.

If Silva is ruled out it will represent a significant blow to City's hopes of reaching a second FA Cup final in three years after they won the 2011 competition. Gareth Barry said: "We can't afford to be missing players like David at this stage of the season. I'm not sure how bad it is, but he would be a big miss in the semi-final. You want players like him to be playing at stadiums like Wembley."

Regarding the clash with Rafael Benítez's side, the midfielder added: "It feels more like a final. We have to show the other semi-final respect, but this is the bigger game of the two, and if we can get through it you never know, this could be another FA Cup for us. I am looking forward to it. You want to be playing big games at this stage of the season, as this is the business end, when they hand out the trophies, and we are lucky we can still win the FA Cup."

Barry is also pleased that Yaya Touré signed a new four-year contract last week. "When a player like him gets a new deal, it is a lift for everyone," he said. "He has been massive for the club since he came, and you don't want to see players like that leaving. You want others like him coming in. When you can keep players like him for another four years, I am sure there will be others coming in, of the same level."

City confirmed they do not expect the police investigation into alleged racist comments aimed at Vincent Kompany at Old Trafford following the derby to uncover any evidence of wrongdoing.